WO2013073346A1

WO2013073346A1 - Internal combustion engine control device

Info

Publication number: WO2013073346A1
Application number: PCT/JP2012/077319
Authority: WO
Inventors: 川辺　敬; 文昭平石; 清隆細野
Original assignee: 三菱自動車工業株式会社
Priority date: 2011-11-18
Filing date: 2012-10-23
Publication date: 2013-05-23
Also published as: EP2781725A1; JP2013108401A; CN103946526B; US20140216414A1; JP6013722B2; CN103946526A; EP2781725A4; US9353697B2; EP2781725B1

Abstract

Provided are a load detection means (2a) which detects the load on the internal combustion engine (10), and an injection amount calculation means (5) which calculates the in-cylinder injection amount injected from an in-cylinder injection valve (11). Also provided are a first control means (2e) which performs first control for raising the frequency of fuel injection from the in-cylinder injection valve (11) when the in-cylinder injection amount has decreased, and a second control means (6) which performs second control for increasing the fuel injection amount from a port injection valve (12) when the in-cylinder injection amount has decreased. Furthermore, a switching control means (7) is provided which, depending on the load, switches between first control by the first control means (2e) and the second control by the second control means (6).

Description

Control device for internal combustion engine

The present invention relates to a control device for an internal combustion engine having an in-cylinder injection valve that injects fuel into a cylinder and a port injection valve that injects fuel into an intake port of the cylinder.

Conventionally, an engine (internal combustion engine) in which two types of fuel injection methods of in-cylinder injection and port injection are compatible has been developed. In such an internal combustion engine, homogeneous combustion in which the concentration distribution of the fuel mixture in the cylinder is made homogeneous and combustion is performed, and stratified combustion in which the high-concentration mixture is burned in a layered manner near the spark plug Are implemented.
In typical fuel injection control, port injection is mainly used during homogeneous combustion, and in-cylinder injection is mainly used during stratified combustion. By properly using the fuel injection method according to the operating state and load of the engine, it becomes possible to improve fuel efficiency while ensuring engine output and stability.

By the way, while the injection valve for port injection is provided in the intake port of each cylinder, the injection valve for in-cylinder injection is provided so that the injection hole portion protrudes into the combustion chamber of each cylinder. For this reason, deposits may adhere to the injection hole portion of the in-cylinder injection valve, which may hinder proper in-cylinder injection. For example, the deposit area may reduce the opening area of the injection hole and reduce the amount of in-cylinder injection, and the fuel injection direction and shape may change, which may reduce the combustibility of the air-fuel mixture. is there.

Therefore, a technique for removing deposits adhering to the in-cylinder injection valve by forcibly in-cylinder injection has been proposed. For example, Patent Document 1 describes control for forcibly changing the fuel injection mode so that only in-cylinder injection is performed even in the operation region where port injection is performed. In this technique, when it is determined that the fuel injection amount of the in-cylinder injection valve has decreased, in-cylinder injection is performed for each predetermined combustion cycle from the in-cylinder injection valve even when port injection is being performed. By such control, it is said that deposits and deposits accumulated in the injection hole portion of the in-cylinder injection valve can be blown away and removed.

JP 2005-201083 A

However, in the conventional technique as described in Patent Document 1, it is determined that the fuel injection amount of the in-cylinder injection valve has decreased, and thus the in-cylinder injection start condition for blowing the deposit is established. For example, in-cylinder injection is performed even when a vehicle equipped with this engine is running and in a driving state where the load acting on the engine is relatively large. At this time, if deposits remain in the injection hole of the in-cylinder injection valve, the engine output corresponding to the magnitude of the load cannot be secured, and the engine operating state may become unstable. There is. On the other hand, if such in-cylinder injection is not performed, it is difficult to remove deposits accumulated in the nozzle holes.

As described above, in the conventional technology, it is difficult to achieve both the control for recovering the injection capacity of the in-cylinder injection valve that has been reduced by the deposit and the control for giving priority to securing the engine output, and the control for implementing these in a balanced manner. There is a problem that setting conditions is not easy.
One of the objects of the present invention has been devised in view of the above problems, and relates to a control device for an internal combustion engine having an in-cylinder injection valve and a port injection valve, and aims to recover the injection capability of the in-cylinder injection valve. While ensuring engine output.
The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) A control device for an internal combustion engine disclosed herein is a control device for an internal combustion engine having an in-cylinder injection valve for injecting fuel into a cylinder and a port injection valve for injecting fuel into an intake port of the cylinder. The load detecting means for detecting the load of the internal combustion engine and the injection amount calculating means for calculating the in-cylinder injection amount injected from the in-cylinder injection valve. In addition, when the in-cylinder injection amount decreases, first control means for performing first control for increasing the frequency of fuel injection from the in-cylinder injection valve; and when the in-cylinder injection amount decreases, from the port injection valve And second control means for performing second control for increasing the fuel injection amount. Furthermore, switching control means for switching between the first control by the first control means and the second control by the second control means according to the load is provided.

The load includes, for example, a required load requested by the driver or various control devices to the internal combustion engine. In addition, parameters such as torque, air volume, and charging efficiency corresponding to the required load are included. Further, the operating state of the supercharger may be regarded as information corresponding to the required load.
In the first control, the first operation region is easily selected when the in-cylinder injection amount is reduced, so that deposits attached to the injection hole portion of the in-cylinder injection valve are easily removed, and the in-cylinder injection amount is recovered. In the second control, the port injection amount is increased to compensate for the decrease in the in-cylinder injection amount, so that the output of the internal combustion engine is ensured.

(2) The switching control means causes the first control means to perform the first control when the load is less than a predetermined load, and when the load is greater than or equal to the predetermined load, the second control means It is preferable to cause the control means to perform the second control.
(3) In this case, a supercharging detection means for detecting an operating state of a supercharger provided in the internal combustion engine is provided, and the switching control means is connected to the first control means when the supercharger is not operating. Preferably, the first control is performed, and the second control means is configured to perform the second control when the supercharger is activated.

(4) It is preferable that a selection means for selecting a first operation region for supplying fuel from the in-cylinder injection valve and a second operation region for supplying fuel from the port injection valve according to the load is provided. In this case, it is preferable that the first control performed by the first control unit is a control for increasing the frequency with which the first operation region is selected by the selection unit when the in-cylinder injection amount is reduced.

(5) The load detecting means detects the amount of air taken into the internal combustion engine as the load and the rotational speed of the internal combustion engine, and the selecting means is based on the air quantity and the rotational speed. The air for selecting one of the first operation region and the second operation region and the first control means for selecting the first operation region when the in-cylinder injection amount decreases. It is preferable to reduce both the amount and the threshold value of the rotational speed.

(6) Also, port injection control means for controlling the amount of port injection injected from the port injection valve, and overlap period control means for controlling the overlap period in which both the intake valve and the exhaust valve of the cylinder are open. It is preferable to provide. In this case, the second control performed by the second control means increases the port injection amount corresponding to the decrease amount of the in-cylinder injection amount and reduces the overlap when the in-cylinder injection amount decreases. It is preferable that the control shortens the period.

According to the disclosed control device for an internal combustion engine, control that restores the injection ability of the in-cylinder injection valve and control that prioritizes output by switching between the first control and the second control according to the load of the internal combustion engine. Can be made compatible without any bias. Thereby, the output of the internal combustion engine according to the load request can be ensured while maintaining the injection capability of the in-cylinder injection valve in a higher state than before.

It is a figure which illustrates the block configuration of the control apparatus of the internal combustion engine which concerns on one Embodiment, and the structure of the engine to which this control apparatus was applied. (A), (b) is a graph for demonstrating the implementation area | region of in-cylinder injection and port injection by this control apparatus. It is a flowchart which illustrates the control which concerns on calculation of the injection capability of the cylinder injection valve implemented with this control apparatus. It is a flowchart which illustrates the control switching procedure implemented with this control apparatus.

The control device will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof, and can be selected or combined as appropriate.

[1. Device configuration]
[1-1. engine]
The control device for an internal combustion engine according to the present embodiment is applied to the on-vehicle gasoline engine 10 (hereinafter simply referred to as the engine 10) shown in FIG. Here, one of a plurality of cylinders provided in the multi-cylinder engine 10 is shown, and this is called a cylinder 20. The piston 19 that reciprocates in the cylinder 20 is connected to the crankshaft 21 via a connecting rod.
Around the cylinder 20, a water jacket 23 serving as a cooling water flow path is provided. A cooling water passage (not shown) is connected to the water jacket 23, and the cooling water circulates inside the water jacket 23 and the cooling water passage.

An intake port 17 and an exhaust port 18 are connected to the ceiling surface of the cylinder 20. An intake valve 27 is provided at the opening of the intake port 17 on the cylinder 20 side, and an exhaust valve 28 is provided at the exhaust port 18. When the intake valve 27 is opened and closed, the intake port 17 and the combustion chamber (inside the cylinder 20) are communicated or closed, and when the exhaust valve 28 is opened and closed, the exhaust port 18 and the combustion chamber are communicated or blocked.
A spark plug 22 is provided between the intake port 17 and the exhaust port 18 with its tip projecting toward the combustion chamber. The timing of ignition at the spark plug 22 is controlled by the engine control device 1 described later.

The upper end portions of the intake valve 27 and the exhaust valve 28 are respectively connected to rocker arms 35 and 37 in the variable valve mechanism 40, and are individually reciprocated in the vertical direction according to the swinging of the rocker arms 35 and 37. The other ends of the rocker arms 35 and 37 are provided with

cams

36 and 38 supported on the camshaft. The rocking pattern of the rocker arms 35 and 37 is determined according to the shape (cam profile) of the

cams

36 and 38. The valve lift amounts and valve timings of the intake valve 27 and the exhaust valve 28 are controlled by the engine control device 1 via the variable valve mechanism 40.

[1-2. Fuel injection system]
As an injector for supplying fuel to the cylinder 20, a direct injection injector 11 (in-cylinder injection valve) that injects fuel directly into the cylinder 20 and a port injection injector 12 (port injection) that injects fuel into the intake port 17. Valve). The fuel injected from the direct injection injector 11 is guided in the vicinity of the spark plug 22 on a layered air flow formed in, for example, a cylinder, and is unevenly distributed in the intake air. On the other hand, the fuel injected from the port injector 12 is atomized in the intake port 17 and introduced into the cylinder 20 in a state of being well mixed with the intake air.

These two types of injectors are also provided in other cylinders (not shown) provided in the engine 10. The amount of fuel injected from the direct injection injector 11 and the port injection injector 12 and the injection timing thereof are controlled by the engine control device 1. For example, a control pulse signal is transmitted from the engine control device 1 to the

injectors

11 and 12, and the injection holes of the

injectors

11 and 12 are opened only during a period corresponding to the magnitude of the control pulse signal. Accordingly, the fuel injection amount becomes an amount corresponding to the magnitude (drive pulse width) of the control pulse signal, and the injection timing corresponds to the time when the control pulse signal is transmitted.

The direct injection injector 11 is connected to a high pressure pump 14A via a high pressure fuel supply path 13A. On the other hand, the port injector 12 is connected to the low-pressure pump 14B via the low-pressure fuel supply path 13B. The direct injection injector 11 is supplied with higher pressure fuel than the port injection injector 12.
Both the high-pressure pump 14A and the low-pressure pump 14B are mechanical variable flow rate pumps for pumping fuel. These

pumps

14A and 14B operate by receiving driving force from the engine 10 or an electric motor, and discharge the fuel in the fuel tank 15 to the supply passages 13A and 13B. The amount of fuel and the fuel pressure discharged from each

pump

14A, 14B are variably controlled by the engine control device 1.

[1-3. Valve system]
The engine 10 is provided with a variable valve mechanism 40 that controls the operation of the rocker arms 35 and 37 or the

cams

36 and 38. The variable valve mechanism 40 is a mechanism for changing the maximum valve lift amount and the valve timing individually or in conjunction with each of the intake valve 27 and the exhaust valve 28. The variable valve mechanism 40 is provided with a valve lift amount adjusting mechanism 41 and a valve timing adjusting mechanism 42 as mechanisms for changing the swing amount and swing timing of the rocker arms 35 and 37.

The valve lift amount adjusting mechanism 41 is a mechanism for continuously changing the maximum valve lift amount of the intake valve 27 and the exhaust valve 28, and controls the magnitude of the swing transmitted from the

cams

36, 38 to the rocker arms 35, 37. Has the ability to change. A specific structure for changing the swinging magnitude of the rocker arms 35 and 37 is arbitrary.
The control parameter corresponding to the valve lift is called the control angle θ _VVL . The valve lift adjustment mechanism 41 has a characteristic of increasing the valve lift as the control angle θ _VVL is larger. The control angle θ _VVL is calculated by a valve control unit 4 of the engine control device 1 described later and transmitted to the valve lift adjustment mechanism 41.

The valve timing adjusting mechanism 42 is a mechanism for changing the opening / closing timing (valve timing) of the intake valve 27 and the exhaust valve 28, and the rotational phases of the

cams

36 and 38 or the camshaft that cause the rocker arms 35 and 37 to swing. With the ability to change. Note that by changing the rotational phase of the

cams

36 and 38 or the camshaft, the rocking timing of the rocker arms 35 and 37 with respect to the rotational phase of the crankshaft 21 can be continuously shifted.

The control parameter corresponding to the valve timing is called the phase angle θ _VVT . The phase angle θ _VVT is an amount indicating how much the phases of the

cams

36 and 38 are advanced or retarded with respect to the phase of the reference camshaft, and each of the intake valves 27 and the exhaust valves 28 is opened. Corresponds to the timing and valve closing timing. Further, the phase angle θ _VVT is calculated by the valve control unit 4 of the engine control device 1 and transmitted to the valve timing adjusting mechanism 42. The valve timing adjustment mechanism 42 arbitrarily controls the valve timing by adjusting the phase angle θ _VVT of each of the

cams

36 and 38.

[1-4. Intake and exhaust system]
The intake and exhaust system of the engine 10 is provided with a turbocharger 30 (supercharger) that supercharges intake air into the cylinder 20 using exhaust pressure. The turbocharger 30 is interposed across both the intake passage 24 connected to the upstream side of the intake port 17 and the exhaust passage 29 connected to the downstream side of the exhaust port 18.

The turbine 30A of the turbocharger 30 is rotated by the exhaust pressure in the exhaust passage 29 and transmits the rotational force to the compressor 30B on the intake passage 24 side. The compressor 30B compresses the intake air on the intake passage 24 side to the downstream side, and supercharges the engine 10. Note that an intercooler 26 is provided on the intake passage 24 downstream of the compressor 30B in the intake air flow to cool the compressed air. The supercharging operation by the turbocharger 30 is controlled by the engine control device 1.

[1-5. Detection system]
At one end of the crankshaft 21, a disc-shaped crank plate 21a provided so that its central axis coincides with the rotation axis of the crankshaft 21, and a crank angle sensor 31 for detecting the rotation angle of the crank plate 21a are provided. . On the outer edge portion of the crank plate 21a, for example, irregularities 21b are formed. On the other hand, the crank angle sensor 31 is fixed in the vicinity of the outer edge of the crank plate 21a, detects the shape of the unevenness 21b of the crank plate 21a, and outputs a crank pulse signal. The crank pulse signal output here is transmitted to the engine control device 1.

The cycle of the crank pulse signal output from the crank angle sensor 31 becomes shorter as the crankshaft 21 rotates faster, and the time density of the crank pulse signal depends on the actual engine speed Ne (engine speed) and the angular speed of the crankshaft 21. It becomes a thing corresponding to. Therefore, the crank angle sensor 31 functions as a means for detecting the engine speed Ne, the crank angle, and the angular velocity.
An oxygen concentration sensor 32 that measures the concentration of oxygen contained in the exhaust is provided at an arbitrary position on the exhaust passage 29. Information on the oxygen concentration detected here is transmitted to the engine control device 1.

In the intake passage 24, an air flow sensor 43 for detecting the air flow rate is provided. The flow rate information detected here corresponds to the intake air amount introduced into the cylinder 20 and is transmitted to the engine control device 1. Further, a fuel pressure sensor 33 for detecting a fuel pressure (fuel pressure) introduced into the direct injection injector 11 is provided on the high pressure fuel supply path 13A. Information on the detected fuel pressure is also transmitted to the engine control device 1.

Accelerator pedal sensor 34 for detecting an operation amount corresponding to the amount of depression of the accelerator pedal is provided at an arbitrary position of the vehicle. The amount by which the accelerator pedal is depressed is a parameter corresponding to the driver's acceleration request, that is, corresponds to an output request to the engine 10. Information on the operation amount detected here is transmitted to the engine control device 1.

[1-6. Control system]
The engine control device 1 (engine ECU) is an electronic control device configured as an LSI device or an embedded electronic device in which a microprocessor, ROM, RAM, and the like are integrated, for example, via a dedicated communication line or an in-vehicle network communication network. Are connected to various sensors such as an electronic control device, a variable valve mechanism 40, a crank angle sensor 31, an oxygen concentration sensor 32, a fuel pressure sensor 33, an accelerator pedal sensor 34, and an air flow sensor 43.

The engine control device 1 controls a wide range of systems related to the engine 10 such as an ignition system, a fuel system, an intake / exhaust system, and a valve system. Specific control objects of the engine control device 1 include the fuel injection amount and its injection timing injected from the direct injection injector 11 and the port injection injector 12, the ignition timing at the spark plug 22, the intake valve 27 and the exhaust valve 28. Examples include the valve lift amount and valve timing, the operating state of the turbocharger 30, the opening of a throttle valve (not shown), and the like.

In the present embodiment, “map change control (first control)” that increases the frequency of in-cylinder injection when the fuel injection capability of the direct injection injector 11 decreases, and similarly when the fuel injection capability of the direct injection injector 11 decreases. The “compensation control (second control)” that covers the injection amount by fuel injection from the port injection valve, and the “switching control” that switches between the map change control and the compensation control according to the engine load will be described in detail.
Further, in relation to the above three types of control, “injection region control” for comprehensively managing in-cylinder injection and port injection, “supercharging control” for controlling the operating state of the turbocharger 30, and direct injection injector 11 The “injection capacity calculation control” for determining the decrease in the fuel injection capacity will also be described.

[2. Overview of control]
[2-1. Injection area control]
The injection region control is control that uses different fuel injection methods such as in-cylinder injection and port injection according to the operating state of the engine 10 and the magnitude of output required for the engine 10. Here, for example, based on the engine speed Ne, engine load, air amount, and charging efficiency Ec (target charging efficiency, actual charging efficiency, etc.), port injection mode in which only port injection is performed and in-cylinder injection are preferentially performed. One of the in-cylinder injection priority modes to be performed is selected.

When the injection mode is selected based on the engine speed Ne and the charging efficiency Ec, it is conceivable to use a control map as shown in FIG. That is, the port injection mode is selected when the engine speed Ne is less than the predetermined speed Ne ₀ and the charging efficiency Ec is less than the predetermined efficiency Ec ₀ . Further, the in-cylinder injection priority mode is selected when the engine speed Ne is equal to or higher than the predetermined speed Ne ₀ or when the charging efficiency Ec is equal to or higher than the predetermined efficiency Ec ₀ .

The filling efficiency Ec means the volume of air filled in the cylinder 20 during one intake stroke (one stroke until the piston 19 moves from the top dead center to the bottom dead center) in a standard state. Normalized to gas volume and then divided by cylinder volume. The actual charging efficiency corresponds to the amount of air introduced into the cylinder 20 in the stroke, and the target charging efficiency is a target value of the charging efficiency Ec and corresponds to the target air amount. In selecting the injection mode, either the actual filling efficiency or the target filling efficiency may be used.

The port injection mode is an injection mode that is selected when the engine 10 is under low load and low rotation. In the port injection mode, fuel injection from the direct injection injector 11 is prohibited, and all the fuel to be injected to obtain the required output is injected from the port injection injector 12. Hereinafter, the amount of fuel injected from the port injector 12 is also referred to as a port injection amount.

The in-cylinder injection priority mode is an injection mode that is selected when the operating state of the engine 10 is not low load and low rotation (other than the port injection mode). In the in-cylinder injection priority mode, in-cylinder injection is performed with priority over port injection. That is, when all of the fuel to be injected in order to obtain the required output can be covered by the injection from the direct injection injector 11, the fuel is injected only by the direct injection injector 11. Hereinafter, the amount of fuel injected from the direct injection injector 11 is also referred to as an in-cylinder injection amount.

On the other hand, the maximum injection amount is set in the direct injection injector 11 due to the restriction of the injection period, and an amount of fuel exceeding this cannot be injected within one combustion cycle. Therefore, when the target value of the in-cylinder injection amount to be injected exceeds the maximum injection amount of the direct injection injector 11, the shortage is injected from the port injector 12 and control is performed to ensure the total fuel injection amount. . In this case, both the direct injection injector 11 and the port injection injector 12 operate in the same combustion cycle, and both in-cylinder injection and port injection are performed.

[2-2. Supercharging control]
The supercharging control is control that determines the operating state (on / off state, operating amount, etc.) of the turbocharger 30 according to the operating state of the engine 10 and the magnitude of the output required for the engine 10. Here, for example, whether or not to operate the turbocharger 30 is determined based on the engine speed Ne or a load acting on the engine 10, and the turbocharger 30 is driven according to the determination result.
As a typical supercharger control method, the turbocharger 30 is driven when a load required for the engine 10 is larger than a predetermined load. The amount of intake air introduced into the cylinder 20 by supercharging increases, and the engine output increases.

[2-3. Injection capacity calculation control]
Since the tip of the direct injection injector 11 is always exposed to the combustion gas in the cylinder 20, deposits may adhere and accumulate in the vicinity of the injection hole. When the deposit adhesion amount increases, the fuel amount actually injected from the direct injection injector 11 decreases from the target fuel injection amount indicated by the control pulse signal. In the injection capacity calculation control, a decrease in the fuel injection capacity of the direct injection injector 11 is calculated (determined and estimated), and this is fed back to the control command value of the direct injection injector 11 to secure a necessary fuel injection amount. To do. The amount of fuel actually injected from the direct injection injector 11 is calculated based on the oxygen concentration in the exhaust gas detected by the oxygen concentration sensor 32, for example.

Further, when it is determined that the fuel injection capacity of the direct injection injector 11 has been reduced, the shortage of fuel accompanying the reduction in capacity is added to the target fuel injection quantity of the direct injection injector 11 so that the actual fuel injection quantity is not insufficient. Is done. At this time, information on the amount of fuel added to compensate for the capacity reduction is stored and learned for each direct injection injector 11 provided in each cylinder 20. When the target fuel injection amount after correcting the decrease in the fuel injection capacity exceeds the maximum injection amount of the direct injection injector 11, the correction amount is added to the fuel injection amount from the port injection injector 12.

Thereby, even when the injection capacity of the direct injection injector 11 is reduced, the total fuel injection amount is secured. However, when the amount of decrease in the fuel injection capacity of the direct injection injector 11 exceeds a predetermined reference value (when deposits accumulate as the injection capacity falls below the reference value), map change control and compensation control described below. One of the above is implemented.

[2-4. Map change control]
The map change control (first control) is one of the controls that are performed when the injection capacity of the direct injection injector 11 calculated by the injection capacity calculation control is reduced. The in-cylinder injection priority mode is set by the injection area control. This is a control that facilitates selection. Here, the selection condition for the in-cylinder injection priority mode is relaxed so that the in-cylinder injection priority mode can be selected even in an operation state in which the port injection mode is selected in the normal state.

When a control map as shown in FIG. 2 (a) is used in the injection region control, the selection condition can be easily changed by changing the control map itself. For example, as shown in FIG. 2B, by using a control map in which the control region corresponding to the in-cylinder injection priority mode is expanded (in other words, a control map in which the control region corresponding to the port injection mode is reduced). This makes it easier to select the in-cylinder injection priority mode.

In this control map, when the engine speed Ne is less than the predetermined speed Ne ₁ smaller than the predetermined speed Ne ₀ and the charging efficiency Ec is less than the predetermined efficiency Ec ₁ smaller than the predetermined efficiency Ec ₀ , the port An injection mode is selected. Further, the in-cylinder injection priority mode is selected when the engine speed Ne is equal to or higher than the predetermined speed Ne ₁ or when the charging efficiency Ec is equal to or higher than the predetermined efficiency Ec ₁ .

[2-5. Compensation control]
The compensation control (second control) is another control executed when the injection capacity of the direct injection injector 11 calculated by the injection capacity calculation control is reduced, and compensates for the decreased injection capacity of the direct injection injector 11. In this way, the fuel injection amount from the port injector 12 is increased. In this compensation control, the shortage of fuel calculated by the injection capacity calculation control is added to the target fuel injection amount of the port injector 12. Thereby, even if it is a case where the injection capability of the direct injection injector 11 falls, the total fuel injection amount is ensured.

The compensation control includes “blow-through suppression control” that prevents and suppresses the port-injected fuel from passing through the cylinder 20 and flowing out to the exhaust passage 29 side. This blow-through suppression control is control for preventing and suppressing port-injected fuel from passing through the cylinder 20 and flowing out to the exhaust passage 29 during the supercharging operation.
Specifically, the following three types of control are performed.
(1) An increase rate of the port injection amount for compensating for the decrease in the in-cylinder injection amount is calculated.
(2) The valve overlap period is shortened according to the increasing rate of the port injection amount.
(3) Delay the port injection timing.

In the blow-off suppression control, the valve overlap period from the exhaust stroke to the intake stroke is shortened, so that the blow-through amount of the air-fuel mixture from the intake port 17 to the exhaust port 18 is suppressed. Further, when the valve overlap period is shortened in accordance with the increasing rate of the port injection amount (the degree of decrease in the in-cylinder injection amount), the amount of air-fuel mixture blown down becomes smaller. Furthermore, by delaying the port injection timing, the time from the start time of fuel injection to the closing time of the exhaust valve 28 is shortened, and the amount of air-fuel mixture blown is reduced.

[2-6. Switching control]
The switching control is control that is performed by switching between the map change control and the compensation control according to the load of the engine 10. In this switching control, one of map change control and compensation control is selected when the injection capability of the direct injection injector 11 decreases.

In this embodiment, the map change control is selected when the turbocharger 30 is in the non-operating state, and the map change control is switched to the compensation control when the turbocharger 30 is in the supercharging state. In addition, it is good also as a structure which refers to the parameter corresponding to the load of the engine 10, such as air quantity and charging efficiency Ec instead of the operating state of the turbocharger 30, or as an additional switching condition.

[3. Control configuration]
As software or hardware for performing the above control, the engine control apparatus 1 includes an injection region control unit 2, a supercharging control unit 3, a valve control unit 4, an injection capacity calculation unit 5, a supplementary injection unit 6, and a switching. A control unit 7 is provided.

A crank angle sensor 31, an oxygen concentration sensor 32, a fuel pressure sensor 33, an accelerator pedal sensor 34, and an air flow sensor 43 are connected to the input side of the engine control device 1, and calculation is performed based on the rotation angle (or rotation angle) of the crankshaft 21. The engine speed Ne), the oxygen concentration in the exhaust, the fuel pressure, the accelerator pedal operation amount, and the intake air amount are input. A direct injection injector 11, a port injection injector 12, and a variable valve mechanism 40 are connected to the output side of the engine control device 1.
The injection region control unit 2 performs injection region control and map change control. The injection region control unit 2 includes a load detection unit 2a, a selection unit 2b, a port injection unit 2c, an in-cylinder injection unit 2d, and a map change unit 2e.

The load detection unit 2a (load detection means) detects a load acting on the engine 10, and here, two types of loads are detected. The first load is a load for injection region control, and is a load for selecting a fuel injection method. For example, in the example shown in FIGS. 2A and 2B, the charging efficiency Ec is used as a load index, and the value of the charging efficiency Ec is detected by the load detection unit 2a. Information about the first load is transmitted to the selection unit 2b.
The second load is a load for map change control, and a load for relaxing the selection conditions for the in-cylinder injection priority mode. In the present embodiment, the operating state of the turbocharger 30 is detected by the load detector 2a as the second load. The information on the second load is transmitted to the switching control unit 7.

The selection part 2b (selection means) selects a fuel injection system according to the 1st load etc. which were detected by the load detection part 2a. Here, for example, the correspondence relationship between the operating state of the engine 10 and the injection mode as shown in FIG. 2A is preset, and the engine speed Ne and the charging efficiency Ec (target charging efficiency, actual charging efficiency, etc.) Based on the above, either the port injection mode in which only port injection is performed or the in-cylinder injection priority mode in which in-cylinder injection is preferentially performed is selected. The port injection mode is selected when the operation state of the engine 10 is relatively low load and low rotation, and the in-cylinder injection priority mode is selected when the operation state is other than that (when other than the port injection mode). .
Hereinafter, the control map stored in the selection unit 2b is referred to as a first control map. The first control map is a control map that is selected while the load on the engine 10 is relatively small. In the present embodiment, the first control map is selected when the turbocharger 30 is not operating.

The port injection unit 2c (port injection control means) performs port injection in the port injection mode. In the port injection mode, a control pulse signal is output from the port injection unit 2c to the port injection injector 12, and port injection is performed according to the control pulse signal. On the other hand, fuel injection from the direct injection injector 11 is prohibited, and all the fuel to be injected to obtain the required output is injected from the port injection injector 12. The port injection unit 2c functions as a port injection control unit that controls the amount of port injection injected from the port injection injector 12.

The in-cylinder injection unit 2d performs in-cylinder injection in the in-cylinder injection priority mode. In the in-cylinder injection priority mode, in-cylinder injection is performed with priority over port injection. That is, when all of the fuel to be injected to obtain the required output can be covered by the injection from the direct injection injector 11, a control pulse signal is output from the in-cylinder injection portion 2d to the direct injection injector 11. The The magnitude of the control pulse signal (drive pulse width) is set to a magnitude corresponding to the target in-cylinder injection amount calculated based on the engine speed Ne and the charging efficiency Ec.

However, the upper limit of the target in-cylinder injection amount is limited by the maximum injection amount of the direct injection injector 11. Further, the magnitude of the control pulse signal output to the port injector 12 is set to a magnitude corresponding to an amount obtained by subtracting the maximum injection amount of the direct injection injector 11 from the target in-cylinder injection amount. When the target in-cylinder injection amount of the direct injection injector 11 is equal to or less than the maximum injection amount, no control pulse signal is output to the port injection injector 12. By such setting of the control pulse signal, the direct injection injector 11 is preferentially driven.

The map change unit 2e (first control means) performs map change control. Here, for example, a correspondence relationship between the operating state of the engine 10 and the injection mode as shown in FIG. 2B is set in advance. The map changing unit 2e functions to increase the frequency of in-cylinder injection by making the selection unit 2b refer to this control map when the amount of decrease in the injection capacity of the direct injection injector 11 exceeds the reference value. However, it is the switching control unit 7 described later that finally determines whether or not to execute the map change control.
Hereinafter, the control map stored in the map changing unit 2e is referred to as a second control map. The second control map is a control map that is selected while the load on the engine 10 is relatively large. In the present embodiment, the second control map is selected when the turbocharger 30 is activated.

The supercharging control unit 3 (supercharging detecting means) performs supercharging control. Here, the engine speed Ne and the magnitude of the load acting on the engine 10 are determined, and when it is determined that the operating state requires supercharging, a control signal for driving the turbocharger 30 is output. .
The magnitude of the load determined here may be calculated based on the accelerator pedal depression amount and throttle opening, or the air amount (target intake air amount, target charging efficiency, actual intake air amount, actual charging efficiency, etc. ). The supercharging execution condition may be set separately from the condition for selecting the injection mode, or may be defined as a predetermined region on the graph shown in FIGS. 2 (a) and 2 (b). Good.

The valve control unit 4 (overlap period control means) controls the operation of the variable valve mechanism 40. Here, the control angle θ _VVL and phase angle θ _VVT of each of the intake valve 27 and the exhaust valve 28 are set according to the operating state of the engine 10, the engine speed Ne, the engine load, and the like. Information on the control angle θ _VVL and the phase angle θ _VVT is transmitted from the valve control unit 4 to the valve lift adjustment mechanism 41 and the valve timing adjustment mechanism 42 of the variable valve mechanism 40.

The injection capacity calculation unit 5 (injection amount calculation means) performs injection capacity determination control. The injection capacity calculation unit 5 includes an actual in-cylinder injection amount calculation unit 5a, a learning unit 5b, and a correction unit 5c.
The actual in-cylinder injection amount calculation unit 5a calculates the actual in-cylinder injection amount based on the oxygen concentration in the exhaust gas detected by the oxygen concentration sensor 32. Here, the amount of oxygen consumed through the combustion reaction is calculated from the difference between the oxygen concentration in the exhaust and the oxygen concentration in the outside air, and the fuel amount corresponding to this oxygen amount is calculated as the consumed fuel amount.

When the in-cylinder injection and the port injection are performed simultaneously, an amount of fuel obtained by subtracting the port injection fuel amount from the calculated fuel consumption amount is calculated as the actual in-cylinder injection amount injected from the direct injection injector 11. . When only in-cylinder injection is performed, the calculated fuel consumption amount is directly calculated as the actual in-cylinder injection amount. The actual in-cylinder injection amount calculated here is transmitted to the learning unit 5b.

The learning unit 5b reduces the actual in-cylinder injection amount calculated by the actual in-cylinder injection amount calculation unit 5a with respect to the target in-cylinder injection amount corresponding to the control pulse signal output from the injection region control unit 2. It is to calculate what has been done. Here, for each direct injection injector 11 provided in each cylinder 20, a short in-cylinder injection amount and a reduction amount of the injection capacity are calculated. The amount of decrease in the injection capacity may be calculated, for example, as a ratio of the actual in-cylinder injection amount to the target in-cylinder injection amount, or may be calculated as a deposit adhesion amount calculated from a short amount of in-cylinder injection amount. The deficient in-cylinder injection amount calculated here is transmitted to the correction unit 5c, and the reduction amount of the injection capacity is recorded in the storage device in the learning unit 5b.

The correction unit 5c causes the injection region control unit 2 to output a control pulse signal that compensates for the in-cylinder injection amount. Here, a control signal for adding the short amount of in-cylinder injection to the in-cylinder injection amount of the direct injection injector 11 calculated by the injection region control unit 2 is output. Thereby, when the learning part 5b detects the fall of the injection capability of the direct injection injector 11, it correct | amends so that the cylinder injection amount after the next time may increase. Further, when the in-cylinder injection amount of the corrected direct injection injector 11 exceeds the maximum injection amount, the port injection amount is corrected to be increased.

The compensation injection unit 6 (second control means) performs compensation control and blow-off suppression control. Here, compensation control is performed when the amount of decrease in the injection capacity of the direct injection injector 11 calculated by the learning unit 5b exceeds the reference value (deposits are accumulated as the injection capacity falls below the reference value), and the fuel The shortage is added to the target fuel injection amount of the port injector 12. In addition, the above three types of blow-through suppression control are performed so that the port injection fuel increased by the compensation control does not blow through to the exhaust passage 29 side.

Corresponding to these three types of control, the supplementary injection unit 6 is provided with a port injection increase ratio calculation unit 6a, a valve overlap change unit 6b, and a port injection timing change unit 6c.
The port injection increase rate calculation unit 6a calculates an increase rate of the port injection amount injected from the port injection injector 12. Here, when the port injection amount is corrected to increase by the compensation control, the ratio of the increment to the port injection amount before correction is calculated as the increase rate. The information on the increase rate calculated here is transmitted to the valve overlap changing unit 6b.

The valve overlap changing unit 6b performs control for shortening the valve overlap (VOL) period in accordance with the increasing rate of the port injection amount. Here, the reduction amount of the valve overlap period is set according to the increase rate calculated by the port injection increase rate calculation unit 6a and the engine speed Ne. An example of setting the reduction amount is shown in Table 1 “VOL restriction map” below. In this setting example, the larger the rate of increase of the port injection amount or the lower the engine speed Ne, the greater the reduction amount of the valve overlap period (the valve overlap period becomes shorter).

The port injection timing changing unit 6 c performs control for retarding the timing of fuel injection from the port injector 12. Here, the retard amount of the port injection is set according to the engine speed Ne. A setting example of the retard amount is shown in Table 2 “Port injection timing map” below. In this setting example, the port injection start time is delayed as the engine speed Ne is lower. The numbers in the table indicate how many times the crank angle at the start of port injection corresponds to the angle before the reference, with the top dead center after the compression stroke as the reference (0 [° CA]) It is.

The switching control unit 7 (switching control means) performs switching control and has a function of switching and executing map change control and compensation control in accordance with a load acting on the engine 10. Here, one of map change control and compensation control is selected based on the second load detected by the load detector 2a.
The switching control unit 7 determines that the load is small when the turbocharger 30 is not operating, selects the map change control, and outputs a signal for causing the map change unit 2e to execute the map change control. On the other hand, when the turbocharger 30 is operated, it is determined that the load is large and the compensation control is selected, and a signal for causing the compensation injection unit 6 to perform the compensation control and the blow-through suppression control is output. Therefore, in a state where the amount of decrease in the injection capacity of the direct injection injector 11 exceeds the reference value, the map change control, the compensation control, and the blow-through suppression control are switched according to the operating state of the turbocharger 30.

[4. flowchart]
[4-1. Normal time]
FIG. 3 illustrates a flowchart relating to injection region control, supercharging control, and injection capacity calculation control among various controls executed by the engine control device 1. This flow is repeatedly performed in the engine control device 1 at a predetermined cycle.

In step A10, information of various sensor detection values such as the oxygen concentration in the exhaust, the engine speed Ne, and the depression amount of the accelerator pedal is input to the engine control device 1. In step A20, the load acting on the engine 10 is detected by the load detection unit 2a. For example, the target charging efficiency of the engine 10 is calculated based on the engine speed Ne, the accelerator pedal depression amount, and the like.
In step A30, based on the load of the engine 10 detected in the previous step, the supercharging control unit 3 determines whether or not the operating state requires supercharging. If the supercharging execution condition is satisfied, the process proceeds to step A40, and after the control signal for driving the turbocharger 30 is output from the supercharging control unit 3, the process proceeds to step A50. On the other hand, if the supercharging execution condition is not satisfied, the process directly proceeds to step A50.

In step A50, the selection unit 2b selects a fuel injection method based on the load of the engine 10 detected in step A20, and determines the type of injection mode. If the injection mode is the port injection mode, the process proceeds to step A70, where the port injection unit 2c outputs a control pulse signal to the port injection injector 12, and the port injection is performed. On the other hand, if the injection mode is the in-cylinder injection priority mode in step A50, the process proceeds to step A60.
In Step A60, a control pulse signal is output from the in-cylinder injection unit 2d to the direct injection injector 11, and in-cylinder injection is performed. When the target fuel injection amount at this time exceeds the maximum injection amount of the direct injection injector 11, port injection is also performed.

In the next step A80, the actual in-cylinder injection amount calculation unit 5a calculates the fuel consumption amount based on the oxygen concentration in the exhaust gas, and calculates the actual in-cylinder injection amount injected from the direct injection injector 11. Thereafter, in step A90, the learning unit 5b calculates how much the actual in-cylinder injection amount has decreased from the target in-cylinder injection amount, and calculates the deficient in-cylinder injection amount. The amount of decrease in the injection capacity grasped here is stored and learned for each direct injection injector 11 provided in each cylinder 20 by the storage device in the learning unit 5b. The learning result is used for in-cylinder injection in the next and subsequent calculation cycles.
Thus, when the deposit is not accumulated so that the injection capacity of the direct injection injector 11 falls below the reference value, the injection region control, the supercharging control, and the injection capacity calculation control are repeatedly performed.

[4-2. When the in-cylinder injection amount decreases]
The flowchart in FIG. 4 relates to map change control, compensation control, and switching control among various controls executed by the engine control apparatus 1. This flow is repeatedly performed at a predetermined cycle in parallel with the flow of FIG.
In step B10, the information on the fuel pressure of the direct injection injector 11, the type of injection mode, the information on the decrease in the injection capacity of the direct injection injector 11 calculated by the learning unit 5b, and the operation of the turbocharger 30 are sent to the engine control device 1. Information about the state is input.

In step B20, in each of the map changing unit 2e and the supplementary injection unit 6, it is determined whether or not the reduction amount of the injection capability of the direct injection injector 11 exceeds a reference value. When the engine 10 is a multi-cylinder engine, the variation in the injection amount of the direct injection injector 11 provided in each cylinder 20 may be determined in this step. For example, it is conceivable to determine whether or not the deviation of the reduction amount for each direct injection injector 11 is a predetermined value or more.

When the determination condition of step B20 is satisfied, it is determined that the deposit has accumulated so that the injection ability of the direct injection injector 11 falls below the reference value, and the process proceeds to step B30. On the other hand, if the condition of step B20 is not satisfied, the process proceeds to step B90.
In step B90, it is determined whether or not the fuel pressure of the direct injection injector 11 is equal to or greater than a predetermined value. The decrease in the injection capacity of the direct injection injector 11 may be caused by, for example, the high pressure fuel supply path 13A or the high pressure pump 14A. In this step, by checking whether or not the fuel pressure is an appropriate value, it is determined whether or not there is a decrease in the injection capacity due to the failure of these fuel systems.

Here, when the fuel pressure is equal to or higher than the predetermined value, it is determined that the injection capacity of the direct injection injector 11 is not lowered, and the process proceeds to Step B100. On the other hand, if the fuel pressure is less than the predetermined value, the process proceeds to step B30.
In step B30, it is determined whether or not the switching control unit 7 and the turbocharger 30 are operating (during supercharging operation). Here, when the supercharging operation is being performed, the switching control unit 7 selects the compensation control and the blow-through suppression control, and the process proceeds to Step B40. On the other hand, when the supercharging operation is not being performed, the map change control is selected by the switching control unit 7, and the process proceeds to Step B70.

In step B40, the port injection increase rate calculation unit 6a of the supplementary injection unit 6 calculates the increase rate of the port injection amount injected from the port injection injector 12. Here, for example, the increase in the port injection amount is calculated based on the decrease amount of the actual in-cylinder injection amount and the fuel pressure, and the ratio of the increment to the port injection amount before correction is calculated as the increase ratio.

In step B50, the valve overlap changing unit 6b sets the reduction amount of the valve overlap period based on the increase rate of the port injection amount and the engine speed Ne. The valve overlap period is shortened as the increase rate of the port injection amount is larger or the engine speed Ne is lower. Further, the shortening amount of the valve overlap period is transmitted to the valve control unit 4, and the phase angle θ _{VVT of the} intake valve 27 and the exhaust valve 28 is controlled according to the shortening amount. The specific control method of each phase angle θ _VVT is arbitrary, and for example, the opening timing of the intake valve 27 may be delayed, or the closing timing of the exhaust valve 28 may be advanced.

In Step B60, the port injection timing changing unit 6c sets the port injection start timing based on the engine speed Ne. The port injection start timing is set to be slower as the engine speed Ne is lower.
When the process proceeds from step B30 to step B70, the map change unit 2e changes the control map related to the setting of the injection mode, and increases the frequency of in-cylinder injection. Thereby, for example, the control map referred to by the selection unit 2b in step A50 of the flow of FIG. 3 is switched from the first control map of FIG. 2A to the second control map of FIG. The in-cylinder injection priority mode is easily selected. In the subsequent step B80, the valve overlap amount at the time of non-supercharging is set, and the control ends. In this case, the normal valve overlap setting is used on the assumption that no fuel blow-through occurs during non-supercharging.

In step B100, which proceeds when the fuel pressure is equal to or higher than the predetermined value in step B90, the map change unit 2e returns the control map related to the setting of the injection mode. For example, the control map referred to by the selection unit 2b in step A50 of the flow of FIG. 3 is switched from the second control map of FIG. 2B to the first control map of FIG. If the control map related to the injection mode setting is not switched to the second control map, the first control map is used as it is.

In Step B110, as in Step B30, it is determined whether or not the switching control unit 7 and the turbocharger 30 are operating (in supercharging operation). Since step B30 is not performed unless the actual in-cylinder injection amount is in a reduced state, the supercharging state in a state in which the actual in-cylinder injection amount is not reduced is determined here. Here, when the supercharging operation is being performed, the process proceeds to step B120, where the normal valve overlap amount at the time of supercharging is set, and the control ends. On the other hand, if not in supercharging operation, the process proceeds to step B80, the valve overlap amount at the time of non-supercharging is set, and the control is terminated.

[5. Action, effect]
According to the above embodiment, the following operations and effects can be obtained.
(1) In the map change control among the controls by the engine control device 1 described above, deposits attached to the injection hole portion of the direct injection injector 11 are easily removed, and the in-cylinder injection amount is easily recovered. Further, in the compensation control, the port injection amount injected from the port injection injector 12 instead of the direct injection injector 11 is increased, so that the decrease in the in-cylinder injection amount is compensated for and the output of the engine 10 is ensured.
In this way, either switching between map change control and compensation control in accordance with the load on the engine 10 allows either the recovery of the injection capacity of the direct injection injector 11 or the control giving priority to securing the output of the engine 10. It is possible to achieve both without being biased. Therefore, the injection capability of the direct injection injector 11 can be maintained in a higher state than before while satisfying the output requirement.

(2) Further, in the engine control apparatus 1 described above, the map change control is performed in a relatively low load state, and the compensation control is performed in a high load state. As described above, by performing the control for recovering the in-cylinder injection amount only when the load is low, the deposit can be removed while securing the output of the engine 10. In addition, since securing output is prioritized over recovery of injection capability at high loads, high output can be obtained.
(3) Further, in the engine control device 1 described above, the map change control and the compensation control are switched according to the operating state of the turbocharger 30. Thereby, the injection capability of the direct injection injector 11 can be recovered at the time of non-supercharging when high output is not required. Further, during supercharging where high output is required, the work for removing the deposit can be temporarily suspended to ensure the output of the engine 10.

(4) In the map change control performed by the engine control apparatus 1 described above, since the in-cylinder injection priority mode is easily selected, the operating region in which fuel is supplied from the direct injection injector 11 can be expanded. The injection ability of the injector 11 can be recovered frequently. Thereby, it is possible to make it difficult for deposits to accumulate in the nozzle hole portion.
(5) Regarding the map change control, the selection unit 2b selects the injection mode based on the engine speed Ne and the charging efficiency Ec. As a result, the operating state of the engine 10 at that time and the magnitude of the load required for the engine 10 can be accurately grasped, and an appropriate engine output can be ensured.

(6) In the compensation control performed by the engine control apparatus 1 described above, the port injection amount corresponding to the amount of decrease in the in-cylinder injection amount is increased, so that the total fuel injection amount can be made constant. The engine output can be maintained. At the same time, the valve overlap period is shortened, so that no blow-by due to an increase in the port injection amount occurs. Therefore, the engine 10 can be operated efficiently while maintaining both engine output and exhaust performance.
(7) Moreover, in said engine control apparatus 1, as shown in Table 1, the valve overlap period is shortened, so that the increase amount of port injection amount is large. That is, the reduction amount of the valve overlap period is set according to the increase rate of the port injection amount, and the effect of suppressing fuel blow-through can be enhanced.

(8) Furthermore, as shown in Table 1, the lower the engine speed Ne, the shorter the valve overlap period. That is, the longer the valve overlap actual time is, the shorter the valve overlap is set, and the fuel blow-out suppressing effect can be further enhanced.
(9) In the engine control apparatus 1 described above, control for retarding the port injection timing is performed. As shown in Table 2, as the engine speed Ne is lower, the retard amount of the port injection valve opening timing is increased. Controlled to increase. That is, the valve opening timing is delayed as the low-rotation operation has a longer real time from when fuel is injected into the intake port 17 until the exhaust valve 28 is closed. Thereby, the fuel blow-through suppressing effect can be further enhanced.

(10) Regarding the calculation calculation of the injection capacity of the direct injection injector 11, the engine control apparatus 1 calculates how much the actual in-cylinder injection amount has decreased with respect to the target in-cylinder injection amount. In this way, by referring to the amount of decrease in the actual injection amount with respect to the control command value, it is possible to eliminate the influence of the calculation error in the engine control device 1 and to accurately grasp the decrease in the injection capacity. .
(11) Further, in the engine control apparatus 1 described above, the actual in-cylinder injection amount is calculated based on the oxygen concentration in the exhaust gas. As a result, the amount of oxygen consumed through the combustion reaction can be accurately calculated, and as a result, the calculation accuracy of the actual in-cylinder injection amount injected from the direct injection injector 11 can be improved.

(12) Further, in the engine control apparatus 1 described above, when the fuel pressure is not equal to or higher than the predetermined value, the blow-through suppression control is performed even if the deposit amount is small. In this way, the cause of the decrease in the in-cylinder injection amount can be specified by referring to the fuel pressure. For example, it is possible to distinguish whether there is a lot of deposits attached to the direct injection injector 11 or whether there is a cause in the fuel piping system. Thereby, it is possible to accurately detect a decrease in the in-cylinder injection amount.

[6. Modified example]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.
In the above-described embodiment, the second load (the operating state of the turbocharger 30) detected by the load detection unit 2a is referred to as the switching condition between the map change control and the compensation control determined by the switching control unit 7. However, the specific switching condition is not limited to this. For example, the map change control may be selected when the air amount or the charging efficiency Ec is less than a predetermined value, and switched to the compensation control when the air amount or the charging efficiency Ec exceeds the predetermined value. By switching these controls using at least a parameter corresponding to the load of the engine 10, the same effect as in the above-described embodiment can be obtained.

Further, in the above-described embodiment, the start condition of the blow-through suppression control is a state in which the turbocharger 30 is operating by the supercharging control, and the injection capacity of the direct injection injector 11 determined by the injection capacity determination control. Although the example in which the decrease exceeds the reference value is exemplified, the specific control start condition is not limited to this. At least, when it is determined that the port-injected fuel is in a state of being easily blown through, the blow-through suppression control may be performed.

In the above-described embodiment, the multi-cylinder gasoline engine 10 is applied to the present invention, but the number of cylinders and the combustion method of the engine 10 are arbitrary.

DESCRIPTION OF SYMBOLS 1 Engine control apparatus 2 Injection area control part 2a Load detection part (load detection means)
2b Selection unit (selection means)
2c Port injection part (port injection control means)
2d In-cylinder injection unit 2e Map change unit (first control means)
3 Supercharging control unit (supercharging detection means)
4 Valve control unit (overlap period control means)
5 Injection capacity calculation unit (injection amount calculation means)
6 Supplementary injection unit (second control means)
7. Switching control unit (switching control means)
11 Direct injection injector (in-cylinder injection valve)
12 Port injection injector (port injection valve)

Claims

In a control apparatus for an internal combustion engine, comprising: an in-cylinder injection valve that injects fuel into a cylinder; and a port injection valve that injects fuel into an intake port of the cylinder.
Load detecting means for detecting a load of the internal combustion engine;
An injection amount calculating means for calculating an in-cylinder injection amount injected from the in-cylinder injection valve;
First control means for performing first control for increasing the frequency of fuel injection from the in-cylinder injection valve when the in-cylinder injection amount is reduced;
Second control means for performing second control for increasing the fuel injection amount from the port injection valve when the in-cylinder injection amount is reduced;
A control device for an internal combustion engine, comprising: switching control means for switching between the first control by the first control means and the second control by the second control means in accordance with the load.
The switching control means is
When the load is less than a predetermined load, the first control means performs the first control,
2. The control device for an internal combustion engine according to claim 1, wherein when the load is equal to or greater than a predetermined load, the second control unit performs the second control.
Supercharging detection means for detecting an operating state of a supercharger provided in the internal combustion engine,
The switching control means is
When the supercharger is not operated, the first control means performs the first control,
The control apparatus for an internal combustion engine according to claim 2, wherein the second control means performs the second control when the supercharger is operated.
Selecting means for selecting a first operation region for supplying fuel from the in-cylinder injection valve and a second operation region for supplying fuel from the port injection valve according to the load;
The first control performed by the first control unit is a control for increasing the frequency with which the first operation region is selected by the selection unit when the in-cylinder injection amount is reduced. Item 5. A control device for an internal combustion engine according to Item 3.
The load detection means detects the amount of air taken into the internal combustion engine as the load and the rotational speed of the internal combustion engine;
The selection means selects one of the first operation region and the second operation region based on the air amount and the rotation speed,
The said 1st control means reduces both the said air quantity and the threshold value of the said rotation speed for selecting a said 1st driving | operation area | region at the time of the fall of the said cylinder injection quantity, Control device for internal combustion engine.
Port injection control means for controlling the amount of port injection injected from the port injection valve;
An overlapping period control means for controlling an overlapping period in which both the intake valve and the exhaust valve of the cylinder are open,
The second control performed by the second control means increases the port injection amount corresponding to the decrease amount of the in-cylinder injection amount and shortens the overlap period when the in-cylinder injection amount decreases. 2. The control apparatus for an internal combustion engine according to claim 1, wherein